Hi, I'm trying to work out why Hotmail are accepting but not delivering mail from my mail servers.

I've got rDNS all set up, and SPF also. I've set up DKIM on one and am in the process of setting it up on others.

If I add the sender address to the 'safe senders' list on my test Hotmail account, it gets through OK. However, if I send from a different local part at the same domain, it does not get through. I've already tried filling out the form for sender support, but they've not done anything other than offer suggestions about managing mailing lists and ensuring that I'm not sending mail to people who don't want it. I'm not using mailing lists, only sending email to genuine customers relating to their account (i.e. no marketing mail) and I'm unable to even send test messages to myself! How do I get Microsoft to fix this?